Pressure variation with heigh is given by

dP/dz = -dg (where dP/dz is differential and d is density and g is acc due to gravity in dg)

For air d= PM/RT

So dP/P = -(gM/RT)dz

gives P(z) =Po*exp(-gMz/(RT))

Where Po is pressure at surface = Patm

and P(z) is pressure at height z

 

Use this to find P(4150) and P(8300) and find difference. I have not done the exact calculation but I think it will come out to be 0.24 atm

(It can never be 2.4 and 24 atm as it must be less than 1 atm)